A solid-state image pickup device includes a light receiving section where M×N pixel units P1,1 to PM,N each including a photodiode and a charge accumulating section are two-dimensionally arrayed in M rows and N columns, a row selecting section that causes each pixel unit Pm,n in a light receiving section to accumulate charge generated in its photodiode during a given period in its charge accumulating section, and to output data corresponding to an amount of the charge accumulated in each pixel unit Pm,n in every row, and a readout section for which the data output from each pixel unit Pm,n in the light receiving section is input and from which data corresponding to an amount of charge generated in the photodiode of each pixel unit Pm,n is output. Also, in some cases, the solid-state image pickup device further includes an AD conversion section that analog/digital-converts the data output from the readout section to output a digital value.
Such a solid-state image pickup device is capable of detecting an intensity of light reaching each pixel unit Pm,n in its light receiving section, to perform image pickup. Further, in recent years, not only image pickup, but an attempt has been made to perform optical communication by using such a solid-state image pickup device. For example, a solid-state image pickup device of the invention disclosed in Patent Literature 1 has a plurality of means for reading out data from each pixel unit, and is capable of performing image pickup by reading out data by every pixel unit with the first readout means among those. Further, the solid-state image pickup device adds current signals generated from photodiodes of specific one pixel unit, or two or more pixel units to output the signal with the second readout means, so that the solid-state image pickup device is capable of receiving an optical signal.